Media-based data storage systems such as magnetic disc drives utilize a wide variety of slider designs. In magnetic data heads, for example, a suspension assembly and actuator are used to position a slider with a transducer or read/write head over a rotating disc or other data storage medium, in order to read and write sequential bit patterns on data tracks defined along the tracking direction of the disc medium. In test heads and media glide heads, the slider is adapted for testing, formatting, calibrating or defect screening of the media. Additional slider designs are configured for use with other forms of media, including digital and analog tape heads, optical data storage heads, and FRAM or FeRAM-based (ferroelectric random access memory) devices.
In disc-based data storage systems, translation of the magnetic medium generates windage along the slider body, causing the media-facing surface to become air-bearing. The slider flies above the medium on the air-bearing surface (ABS), reducing wear and tear as compared to contact-based technologies. The fly height and slider attitude must be carefully regulated, however, in order to provide optimal performance, and precise actuator and suspension control is required to avoid slider-media contact.
Contact events typically occur during disc startup and shutdown, or due to power loss, mechanical malfunction, physical shock and vibrations. To address this problem, a landing zone or contact start/stop (CSS) area is sometimes defined in a data-free section of the medium, for example along the inner diameter (ID) of a magnetic disc. The slider is positioned in the CSS area during startup/shutdown, and in the event of unexpected power loss or shock-related events, typically using a spring mechanism or the rotational inertia of the disc to position the slider. Often, the CSS is provided with laser-zone texturing (LZT) or other surface features to reduce friction and stiction (static friction) on restart.
Alternatively, a load/unload (L/UL) system is used to lift the slider off the storage medium when not in use. The L/UL approach reduces friction, stiction and other wear effects by relocating the head to an unload area or L/UL ramp, which is located off the data storage medium. L/UL techniques also provide “green drive” features by allowing the head to be parked on the L/UL ramp during idling, and facilitate system-level active protection systems using acoustic transducers and accelerometers or g-sensors to control L/UL operations when the disc drive (or the computer system containing the disc drive) is subject to shock or vibration.
Even in advanced CSS and L/UL designs, however, the risk of slider-media contact remains. This is particularly true, for example, when the disc system is dropped or struck, or when slider attitude and position are not optimally controlled during load/unload events. Thus there remains a constant need for improved slider designs that reduce the potential risk and severity of media contact events, and which are adaptable to a wide range of disc drives and other non-volatile data storage systems.